Air-brake system.



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N0. 705,592. Patented luly 29, |902.

W. G. MAGLAUGHLIN.

AIR BRAKE SYSTEM. (Applicaftion filed May 11, 1901.)

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UNITED STATES PATENT OFFICE.

" WILLIAM GQMCLAUGHLIN, OF WINDSOR, CANADA, ASSIGNOR TO THE MACLAUGHLINRAILWAY BRAKE COMPANY, OF DETROIT, MICHIGAN,

AIR-BRAKE SYSTEM.

SPECIFICATION forming part of Letters Patent No. 705,592, dated July 29,1902.

.y Application tiled May l1, 1901A.

To @ZZ whom t may concern:

Be it known that LWILLIAM G. MACLAUGH- LIN, a citizen of the UnitedStates, residing at Windsor, in the county of Essex, Province ofOntario, Canada, have invented certain new and useful Improvements in4Air-lrake Systems; and I do declarefthe following to be a full, clear,and exact description of the invention, such as will enable othersskilled in the art t-o which it appertains to make and use the same,reference being had to the accompanying drawings, and to the iigures ofreference marked thereon, which form a part of this specification.

This invention relates to au air-brake system; and it consists in theconstruction and arrangement of parts hereinafter fully set forth, andpointed out particularly in the claims.

The object of the invention is to provide simple and eflicient means forreadily applying the brakes through the mediumof air or other iuidpressure in which the arrangement is such as to render thesystemadaptable to a single car or to a series of cars, as desired. A furtherarrangement provides for an immediate application or release of thebrakes, the holding of the brakes in releasevby an excess. ofair-pressure uponone side of the piston of the brake-cylinder, and theadmittance of air to the brake-cylinder in such volume and under suchcontrol as to prevent so sudden an application of thebrake as iscalculated to slide the wheels and iattenthe face thereof.`

The above object is attained by the mechanism illustrated inthe'accompanying drawings, in which- Figure l is a plan view of thebrake system as applied to a single car, showing the train-` pipe bywhich additional cars may be connected, if desired. Fig. 2 is alongitudinal section through the brake-cylinder and the sliding sleeveor guide connected with the piston-rod to guide it in its movement. Fig.3 is a sectional View showing the connection between the auxiliaryreservoir and the brakecylinder. Fig. 4 is a diagrammatical view showingthe system as employed on a number of cars, as in a train.` Fig. 5 is aplan view of the engineers brake-valve,through the me- Serial No.59,741. (No model.)

dium of which the brakes are operated. Fig. 6 is a sectional Viewthrough said valve.

Referring to the characters of reference, l

designates the engineers brake-valve, mount-- ed within a suitablevalve-case 2 and located in the cab or motormans vestibule, where it maybe conveniently operated. Said valve is provided with a curved way 3therethrough, whereby the passage of air to the various parts of thesystem may be controlled by the operation of said valve through themedium of the handle 4. l l

Communicatingwith the valve-case 2 is an air-pipe 5, connected with theair-pump 6, which may be driven from any suitable source of power. Alsocommu nicating with the valvecase 2 is the train-pipe 7, whereby airfrom the pump may be forced'into said train-pipe and into the mainreservoir 8, which is connected with the train-pipe through thepipesection 9, having therein a byway-valve 10, which allows the air toflow into said reservoir from the train-pipe, but automatically preventsthe return of the air to the train-pipe from said reservoir.

The brake-cylinder ll is connected at one end to the train-pipe by meansof the pipesection 12, whereby the pressure ofthe trainpipe is presentin the forward end of' the brake-cylinder. In the pipe 12 is a cut-0Evalve 13, which allows the pressure to be cut off from thebrake-cylinder, if desired. The auxiliary reservoir let is connected tothe main reservoir 8 through the'pipe l5, having a reducing-valve 16therein of any suitable construction, which allows of the' passage ofair from the main reservoir to the auxiliary reservoir until thepressure withinthe auxiliary reservoir reaches a point Within ivepounds, more or less, of that of the'main reservoir, when saidreducing-valvewill cut oi any further flow of air to the auxiliaryreser-Voir and maintain a pressure-therein below the point of said mainreservoir. A valve 17 in the pipe l5 allows the air to be cut olf toprevent its escape from the auxiliary reservoir when it is desired toretain the air-pressure therein for some considerable time when thesystem is not in operation. Leading from the end of the auxiliaryreservoir opposite to thereon and impinges against the end 22 of asleeve 23, adapted to slide horizontally upon a cylindrical support 24.Said support 24: is made fastin anysutable manner and is provided with alongitudinal bore adapted to receive the brake-rod 25, which slidestherein and the inner end of which passes into terminal contact with theend 22 of the sleeve 23. By this arrangement it will be seen that as thepiston-head 19 moves forward in the brake-cylinder the piston-rod 20will engage and slide the sleeve 23 upon its guiding-support 24, therebymoving the brake-rod 25 longitudinally and actuating the brakemechanism. lt will also be seen lthat the brake-rod may have movementindependently of the sleeve 23, whereby provision is made for the.application of brakes by hand when required,

as said brake-rod` may be retracted longitudinally-in the support 24without affecting the position of the piston within the brake-cylinder.

Itwill now be understood thatthe pressure within the main reservoir, thetrain-pipe, and the forward end of the brake-cylinder is normally thesame and that said pressureisin excess of that carried in the auxiliaryreservoir connected with the rear end of the brake-cylinder, so that thepressure in the auxiliary reservoir is overcome by that within theforward end of the brake-cylinder, whereby the piston 19 thereofismaintained in the position shown in Fig. 2, and the brakes are heldreleased. When it is desired to apply the brakes, the brake-valve ismoved so as to connect the train-pipe 7 by way of the passage 3 in saidvalve with the port 26 in the valvecase,which opens to atmosphere,whereby the air may be permitted to exhaust the trainpipe until thepressure therein is reduced be-` low that of the auxiliary reservoir14:, when the pressure from said reservoir will overcome that in theforward end of the brakecylinder and allow the air in said auxiliary toexpand into the rear of' said cylinder through the pipe 18, therebyforcing the piston 19 to the forward end of the brake-cylinder and.actuating the brake mechanism to apply the may be reduced toatmosphere, allowing the brakes to be applied with all of the pressurecontained in the auxiliary reservoir. After an application of the brakesthey are released by turning the brake-valve so as to connect thetrain-pipe 7 with the-air-pipe 5, leading from the pump, when thepressure in'the train-pipe may be restored to the normal, therebycreating an excess of pressure in the forward end of the brake-cylinderand forcing the piston backto the position shown in Fig. 2, therebyreleasing the brakes. The air which expanded into the rear of thebrakecylinder from the auxiliary in the act of applying the brakes is bythe return of the piston forced back into the auxiliary, whereby thepressure in the auxiliary becomes restored to the normaland a waste ofair from the auxiliary in the operation of braking is obviated. Shouldthere have been an escape of air in the operation of applyingthe-brakes,

so as to reduce the pressure in the auxiliary` below the normal, saidkpressure'will be alito- Inatically raised or restored through theoperation of the reducing-valve 16. The pressure in the auxiliary issupplied from the main 'reservoir 8, in which the pressure is maintainedat the required degree through the medium of the pump when connectedwith the train-pipe, whereby the air-may be forced into the mainreservoir through the l pipe 9.

The byway 10 in the pipe 9 comprises a spring-actuated plunger carryinga piston 27, which closes the pipe 9 and which is caused to recede bythe pressure from the train-pipe, so as to expose the channel 28,through which the air may pass into the reservoir 8, until the pressuretherein equals that of the trainpipe, when said piston will seat andprevent any outward iow of air through the pipe 9 from said reservoir 8.By this arrangement the air is prevented from escaping from the mainreservoirs should the train-pipe break, thereby insuring the efficiencyof the brake in such an emergency.

The pipe 18, connecting the auxiliary reservoir with the rear of thebrake-cylinder, is comparatively small, the purpose of which is toprevent a sudden expansion of the air -in the rear of the brake-cylinderat thefull pressure of the auxiliary when the pressure in the forwardend of the cylinder has been reduced through the opening of thetrain-pipe to atmosphere, as a sudden occupation of the rear of thebrake-cylinder by the air at the full pressure of the auxiliary wouldmove the piston therein so rapidly and forcibly as to jam thebrake-shoes against the wheels and set or lock them from turning,thereby causing the Wheels to slide and wear flat surfaces on theirtreads. By reducing the pipe through which the air expands into thebrake-cylinder from the auxiliary thev volume and pressure of air in thebrake-cylinder is not so quickly increased, allowing the brake-beamafter the first impulse to settle back and permit the IOO IIO

shoes to gradually set themselves 'to the wheels, the piston-head inthebrake-cylinder being allowed to vibrate or pulsate until thebrake-shoes are nally forced against and held in contact with thewheels, alnatter of great importance, as the sliding of the wheels bythis means is almost entirely obviated.

Where the air-brake systemllerein ex` plained is employed onta train,the air-pipe 7 is used to supply air to all the main reservoirs, and themain reservoir for each car is connected, as shown, with an auxiliaryreservoir, so that by exhausting the air from the train-pipe to cause adiminution of pressure therein all of the brakes of the train will besimultaneously applied, and the restoration of pressure in thetrain-pipe will in like manner release allof the brakes, When the systemis used on a single car, the train-pipe will be dispensed with beyondthe connection with the brake-cylinder, and a pipe 29 (shown by dottedlines in Fig. l) will connect the main reservoir directly with thebrake-valve, so that by theoperation of said valve the pump maybeconnected with the main reservoir t restore the pressure therein.

The dotted lines shown in Fig. 3, and which parallel the pipe '18 `andthe cylinder 20, are drawn to indicate 1the relative size of said pipecompared with the diameter of the cylinder. The solid lines `indicatethe normal size of said parts, while the dotted lines show a comparativeincrease in the size of the pipe and cylinder. The purpose of thisarrangement is to maintain the same relative area between the cylinderand the pipe 18, so thatthe volume of air admitted to the cylinderthrough said pipe will at all times be such as to insure a perfectoperation of the brake and obviatev an` excessive pressure in thebrakecylinder calculated to supply the brakes with such `force as toslide the wheels.

Having thus fully set forth my invention, what I claim as new, anddesire to secure by Letters Patent, is-

l. In a brake mechanism, the combination of a brake-cylinder having apiston therein connected with a brake mechanism, a trainpipe connectedwith the forward end of the brake-cylinder upon one side of the pistontherein, an auxiliary reservoir connected withl the rear of thebrake-cylinder upon the opposite side of the piston, a main reservoirconnected with the train-pipe and adapted to carry pressure equal to thetrain-pipe pressure, means connecting the auxiliary reservoir with themain reservoir to reduce the pressure in said auxiliary and maintain itnormally below that of the train-pipe, means for reducing the train-pipepressure below thatof the auxiliary reservoir and means forV restoringthe train-pipe pressure to a point in excess ofthe pressure of saidauxiliary.

2. In an air-brake system the combination of a main reservoir, abrake-cylinder, a piston in said cylinder connected'with a brakemechanism, an air-pipe adapted to contain a relatively high pressureconnected with the forward end` of the brake-cylinder, an auxiliaryreservoir adapted to normally contain a relatively low pressureconnected to the opposite ends of the brake-cylinder bya pipe ofcomparatively small area, said auxiliary reservoir being also connectedwith the high-pressure pipe by way of the main reservoir,`1neans forreducing the pressure in Vsaid'air-pipe below that of the auxiliary`reservoir and restore said pressure to the normal above that of theauxiliary.

3. In an air-brake system, the combination of the brake-cylinder havinga piston therein eonneetedfwith a brake mechanism, a trainpipe connectedwith the brake-cylinder on one side of said piston, a main reservoirconnected with the train-pipe bya pipe containing a valve which allowsthe air to flow from the train-pipe into said main reservoir, butprevents the fiow of air from the main reservoir to the train-pipe, anauxiliary reservoir connected to the brake-cylinder on the side of thepiston opposite to that of the train-pipe connection, means forconnecting the main reservoir with the auxiliary reservoir adapted toallow ofthe passage .of air into said auxiliary reservoir at a pressurebelow that of the main reservoir and the train-pipe, and means foralternately reducing the trainpipe pres- IOO therein connected byapiston-rod with a brake mechanism, a train-pipe containing air-pressureconnected withi the brake-cylinder on one side of said piston and anauxiliary reservoir, normally containing a pressure below that of thetrain-pipe, means for reducing and restoring the pressure of thetrain-pipe, a pipe connecting the auxiliary reservoir to the train-pipethrough the main reservoir and a pipe connecting the auxiliary reservoirto the brake-cylinder of a relatively small diameter to prevent a suddenexpansion of the air in the rear of the brake-cylinder when the pressurein the forward end thereof is reduced.

5. In an air-brake the combination of a IXO brake-cylinder havin g apiston therein, a main reservoir, a primary air system containing arelatively high pressure connected with the main reservoir, a closedsecondary air system.

